This invention relates to adjustable foot equipment for such activities as snow skiing, snowboarding, water skiing, roller skating, ice skating, walking and running.
It is well known that the most prevalent posture conditions or categories of a person's legs are legs which are commonly referred to as bowing inwardly toward each other, bowing outwardly and away from each other, and legs which are in a substantially vertical orientation. In various other leg posture conditions, the leg orientation can deviate slightly inwardly or outwardly from a vertical reference plane located between the legs.
The particular leg orientation which is optimal for different sports is debatable and subject to considerable differences of opinion. In skiing, for example, given current designs of boots and skis, it is considered optimal for the legs to be oriented approximately vertically.
Foot engageable equipment used in skiing is generally designed to fit an "average user's" leg orientation in a standing position relative to the ground. However, the so-called "average user's" leg orientation is not necessarily a vertical orientation. Because many people do not have leg orientations that conform to the target leg orientation that is designed into a particular piece of foot engageable equipment, such equipment may exaggerate an individual's leg deviation from the vertical reference plane, which in many instances is undesirable.
Consequently, depending upon an individual's normal leg orientation, foot engageable equipment can place the legs in a position that is either beneficial or detrimental to the user's performance. This in turn may lead to increased or decreased performance proficiency, depending on the user, and the application.
The term "off-vertical leg orientation" is intended to refer to the amount of deviation of an individual's legs from a vertical reference plane between the legs. Off-vertical leg orientation can be measured while the foot engageable equipment is being worn and the user is standing in what is considered a "normal" standing position, or when the user is not wearing any foot engageable equipment. For discussion purposes, it will be assumed that vertical leg orientation with foot equipment being worn is the desired objective for obtaining optimal performance and proficiency.
Thus, in skiing, the optimal leg posture position with foot engageable equipment is considered to be a position of vertical orientation while the ski bases are horizontally flat on the snow. Preferably the orientation of the legs should be symmetrical.
During turns, rotational and angular movements of the legs and body are used to turn and edge the skis as well as create desirable body positions. These movements serve a dual purpose of creating direction changes as well as placing the center of mass of the body in a position to balance against the forces generated while turning.
A skier who starts out with an off-vertical leg orientation may be unable to simultaneously create both the proper edge angle and body tilt necessary for proficient turning movements. This forces the skier to compensate by using exaggerated or inefficient movement patterns as part of his or her technique, such as overuse of femoral rotation, excessive abduction of the knee joint, hip flexion, etc.
It is thus well known that skill development and proficiency in skiing are usually easier to accomplish if one's leg orientation is vertical wherein the side edges of the ski are generally in a plane that is substantially horizontal to the ground. Skiers whose leg orientation deviates from the vertical, such that there is an off-vertical leg orientation, experience difficulty in both balancing and edging abilities. Such skiers have recently been the focus of numerous attempts to compensate for the off-vertical condition.
For example, U.S. Pat. No. 3,732,635 to Marker shows a ski boot upper that is pivotal with respect to a tub-like sole. Pivotal adjustment is accomplished via front and rear brackets that permit universal adjustment of the upper relative to the tub-like sole. However, this structure is difficult to adjust, and once adjusted can easily go out of adjustment because of relative flexion between the brackets.
U.S. Pat. No. 4,078,322 to Dalebout shows heel and toe piece elements for a ski boot to provide specific cant angles adapted to a particular skier's needs. The heel and toe pieces can either be standard stock items provided in specific angular increments or a custom-made heel and toe piece for individual requirements. A further variation of this theme is shown in U.S. Pat. No. 5,293,702. Neither of these patents show a device that permits simple readjustment from one angular condition to another.
U.S. Pat. No. 4,945,659 to DeMarchi et al shows sole portions adapted to fit on the front and rear tenons of a ski boot to provide desired correction for a bow-legged or knock-kneed skier. This device also does not permit simple readjustment from one adjusted condition to another.
U.S. Pat. No. 4,601,118 to Zanatta shows an inclination adjustor provided on an upper portion of a boot to adjust the inclination of the upper portion relative to the lower portion. This device is also difficult to change when readjustment is necessary.
It is thus desirable to provide a simple adjustable means for foot equipment that compensates for off-vertical leg orientation that is relatively easy to use and permits further readjustment when needed. It is also desirable to provide adjustment means adaptable to different foot equipment used for different activities.